Cross-checking a listening history against a dozen venue calendars
Working out which of the bands you already listen to are coming through town means opening your streaming history in one tab and a dozen venue calendars in another, then doing the whole thing again next month. Nobody keeps that up, so people hear about the show the week after it happened. Concerts For You does it instead: you hand it the listening history you can export from Spotify or YouTube in about a minute, it reads the artist names out of the file, and it checks what is on sale inside the distance you are actually willing to drive.